1. Field of the Invention
This invention relates to a method and apparatus for inhibiting a scattered component in a light having passed through an examined object adapted to make the information within the inspected object visible by using a light in order to help the perspective of a living body by a light, the cross-sectioned image photographing of a living body by a light, the non-destructive inspection of the internal structure of a semiconductor or IC or the work in mist, snow or water.
2. Related Art Statement
Recently, with the increase of the diseases of the heart circulatory system and brain vein system and with the prevalence of the image utilization in the diagnosis, the importance of vein imaging has increased. However, although vein imaging has become comparatively easy due to the progress of digital radiography, the danger and pain experienced by the examinee when vein imaging is applied to a human body must be considered.
Heretofore, the non-invading or non-contacting measurement of the information within such examined object as a living body has been made mostly by x-rays. However, the use of x-rays is known to cause radiation of radioactive rays and their use is poorly adapted for imaging a living body function. Also, the NMR-CT method has the problem that the apparatus is large and expensive. The perspective obtained by ultrasonic waves suffers from low spatial analyzing activity. Heretofore, it has been considered that the living body or IC substrate is non-transparent and the interior can not be viewed by using a light.
It is well known that blood hemoglobin (Hb) shows a peculiar spectral variation in response to the oxygenizing degree against the light in the near infrared region. By utilizing this feature, as shown, for example, in the article "Living Body Measurement by Using Light" found in the magazine "O plus E" May 1987 to March 1988, research relating to such non-invading measurement of the information within a living body, such as the measurement of the oxygen saturation degree of blood, are being actively made. The blood hemoglobin (Hb) absorbs so much more light in the infrared region than living body tissue that the possibility of detecting a light image of a vein in the tissue is considered feasible.
However, where the living body interior is observed from outside the body by using a light, because of strong light scattering of the tissue within or without the body, the contrast will be reduced and it will be difficult to make the information of the interior of a living body visible. It is expected that, if the problem of this light scattering can be solved, the shape and variation of a vein within the body will be able to be made visible with an actual time and to be measured. It is expected that, from the thus obtained body interior information, on the basis of a knowledge of spectral science, the information of not only the shape but also the metabolic function of the living body can be obtained.